A man wears a metrocar hat as he travels on the red line of the metro in Washington October 30, 2015. (Photo by Carlos Barria/Reuters)

Dakota Bourdon rounds the corner to be greeted by a zombie at the Apocalypse Zombie Experience at The Walker Stalker Convention in Atlanta, Georgia, October 30, 2015. The convention also showcases advanced special effects and cosplay techniques along with the stars of "The Walking Dead" television show and various other type shows. (Photo by Tami Chappell/Reuters)

A volunteer walks past a carpet for sale as he walks with children participating in the School on Wheels Skid Row Halloween Parade for children who live in shelters, motels, cars and on the street, in Los Angeles, California, United States, October 30, 2015. (Photo by Lucy Nicholson/Reuters)

Children participate in the School on Wheels Skid Row Halloween Parade for children who live in shelters, motels, cars and on the street, in Los Angeles, California, United States, October 30, 2015. (Photo by Lucy Nicholson/Reuters)

Children participate in the School on Wheels Skid Row Halloween Parade for children who live in shelters, motels, cars and on the street, in Los Angeles, California, United States, October 30, 2015. (Photo by Lucy Nicholson/Reuters)

Children participate in the School on Wheels Skid Row Halloween Parade for children who live in shelters, motels, cars and on the street, in Los Angeles, California, United States, October 30, 2015. (Photo by Lucy Nicholson/Reuters)

A woman walks down a stairway partially filled with decorations in the shape of carved pumpkins to celebrate Halloween in Shenyang, Liaoning province, China, October 30, 2015. (Photo by Reuters/Stringer)

A volunteer walks with children participating in the School on Wheels Skid Row Halloween Parade for children who live in shelters, motels, cars and on the street, in Los Angeles, California, United States, October 30, 2015. (Photo by Lucy Nicholson/Reuters)

A cosplayer poses for photographs at the 2015 Comic Fiesta event in Kuala Lumpur, Malaysia, October 31, 2015. (Photo by Olivia Harris/Reuters)

Residents visit the grave of a departed loved one inside a public cemetery in Makati financial district of Manila October 31, 2015. Filipinos flock to cemeteries across the country to commemorate their departed loved ones for All Saints and All Souls Days, which fall on November 1 and 2 respectively. (Photo by Janis Alano/Reuters)

Relatives and the friends of passengers aboard the Metrojet flight that crashed in Egypt react while gathering to grieve at a hotel near St. Petersburg's Pulkovo airport outside St.Petersburg, Russia, Saturday, October 31, 2015. Russia's civil air agency is expected to have a news conference shortly to talk about the Russian Metrojet passenger plane that Egyptian authorities say has crashed in Egypt's Sinai peninsula. (Photo by Dmitry Lovetsky/AP Photo)

Relatives of victims of a Russian airliner which crashed in Egypt, mourns at a hotel near Pulkovo airport in St. Petersburg, Russia, October 31, 2015. The Airbus A321, operated by Russian airline Kogalymavia under the brand name Metrojet, carrying 224 passengers and crew crashed in Egypt's Sinai peninsula on Saturday after losing radar contact and plummeting from its cruising altitude, killing all aboard. (Photo by Peter Kovalev/Reuters)

A relative of victims of a Russian airliner which crashed in Egypt, mourns at a hotel near Pulkovo airport in St. Petersburg, Russia, October 31, 2015. (Photo by Peter Kovalev/Reuters)

A woman reacts at Pulkovo airport in St. Petersburg, Russia, October 31, 2015. (Photo by Peter Kovalev/Reuters)

People sunbathe as they take advantage of warm autumn weather temperatures on the beach in Marseille October 31, 2015. (Photo by Jean-Paul Pelissier/Reuters)

Sheep graze in a marsh field in Le Mont-Saint-Michel, France, October 31, 2015. (Photo by Stephane Mahe/Reuters)

A woman takes part in a zombie walk during Halloween celebrations in Berlin, Germany, October 31, 2015. (Photo by Hannibal Hanschke/Reuters)

Children take part in Halloween celebrations in La Fresneda, northern Spain, October 31, 2015. (Photo by Eloy Alonso/Reuters)

Laurence Fournier Beaudry and Nikolaj Sorensen of Denmark perform during the Ice Dance free dance program at Skate Canada International in Lethbridge, Alberta October 31, 2015. (Photo by Jim Young/Reuters)

AS Roma's Mohamed Salah (top) is challenges Inter Milan's Fredy Guarin during their Italian Serie A soccer match at the San Siro stadium in Milan, Italy, October 31, 2015. (Photo by Alessandro Garofalo/Reuters)